| 摘要 |
PROBLEM TO BE SOLVED: To impart retention resistance, chemical resistance, water resistance and friction resistance without impairing physical properties such as mechanical strength and elongation by covering the surface of an elastic material with a coating layer containing fluorine set within a specified film thickness range. SOLUTION: A tube 1 for a pinch valve is manufactured, for example, using an ethylene propylene rubber, and a coating layer containing fluorine with 0.3-4μm thickness is applied to cover both inner surface and outer surface of the tube 1 by a gas phase fluorine treatment. Thus it is possible to control the mutual retention of rubbers by applying the coating layer, and further suppress the qualitative deterioration of the rubber by hypochlorous acid contained in a tap water. In addition, the tube 1 does not show any durability change and the frictional resistance of the tube 1 is reduced, resulting in the ability to prevent the tube 1 from being worn out by a pressing member 2 by coating the outer face of the tube 1. Besides the resistance to retention of the elastic material can be enhanced by setting the coating layer within the specified range of thickness.
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